presidential debate in denver wednesday night. romney is holding a rally in the mile-high city today, while the president gears up in nevada. nbc's tracie potts joins us from washington with the latest. >> reporter: good morning, everyone. we get an interesting perspective on this from john mccain, he's debated both the president and mitt romney. he says we will see two very strong well-prepared debaters and he predicts few surprises. the president's behind closed doors in nevada for the next two days preparing to face mitt romney in denver wednesday. >> he's a good debater. i'm just okay. but what i'm most concerned about is having a serious discussion about what we need to do to keep the country growing. >> reporter: both sides are downplaying expectations. a senior aide to the president says romney will be prepared, disciplined and aggressive. romney's debate partner calls the president a tough debater. >> barack obama is going to be formidable, and i think it will be a good debate, but i certainly would not underestimate what